Lubricating oil compositions for motorcycles

ABSTRACT

Disclosed is a MoDTC-free lubricating oil composition for motorcycles which comprises an engine and a clutch, wherein the composition comprises: an oil of lubricating viscosity, a molybdenum compound, and a salicylate detergent having a TBN 100-450 on active basis, wherein the composition lubricates the engine but not the clutch. 
     Also disclosed is a method for lubricating the engine of a motorcycle, which comprises an engine and a clutch, with a MoDTC-free lubricating oil composition, wherein the composition comprises: an oil of lubricating viscosity, a molybdenum compound, and a salicylate detergent having a TBN 100-450 on active basis, and wherein the composition lubricates the engine but not the clutch.

FIELD OF THE INVENTION

The present invention generally relates to lubricating oil compositionsuseful for motorcycles.

BACKGROUND OF THE INVENTION

Lubricants for motorcycles typically provide lubrication for the engine(a crankcase) and a wet clutch. These two devices, although oftenlubricated by the same fluid, often have different lubricationrequirements. For example, the lubrication of the engine desirablyprovides low “metal-on-metal” friction interface to promote good fueleconomy. Typically, the “metal” referred to is steel. However, thefriction coefficient for the “metal-on-composition” interface, whichoccurs within the wet clutch, is typically desired to be relativelyhigh, to assure good engagement and power transmission. Additionally,motorcycle lubricants also lubricate other devices such as gears orbearings, each having their own lubrication requirement.

Many lubricants have been designed over the years for lubrication ofmotorcycles (also known as motorbikes or motorscooters). One suchlubricant is described in U.S. Patent Publication 2008-0096778. Breon etal., Apr. 24, 2008.

Four-stroke motorcycle engine lubricants may appear to be similar topassenger car engine lubricants. However, there are several keyengineering design features of motorcycles, such as integration ofclutch and gearbox, high speed of operation, high specific power output,low sump volumes, and lightweight engine construction, all of whichrequire additional consideration when formulating motorcycle oils.Because of the varied and demanding lubrication performance required,motorcycle lubricants are typically designed specifically for use inmotorcycles. That is, typical lubricants as used in lubricatingpassenger car engines are not normally used for motorcycles.

Nevertheless, there are a certain number of motorcycles which do notemploy a wet clutch, but, rather, “dry” or non-lubricated clutches orclutch plates. Likewise, there might be motorcycles for which a wetclutch is lubricated by a separate lubricant from that used to lubricatethe engine. For those motorcycles, the high metal-on-compositionfriction is of no benefit to the engine and is indeed undesirable to theextent that it may interfere with the provision of the lowest possiblefriction in the metal-on-metal interlaces. While one possible approachto solving this problem would be to remove from the lubricant thosecomponents that provide high metal-on-composition friction, this is notnecessarily desirable. The additives within such lubricants are usuallycarefully balanced, so that the removal of one component may affect theperformance of the lubricant in unintended ways. Furthermore, it may beundesirable, from a commercial standpoint, to stock multiple completemotorcycle lubricants: some for motorcycles with a wet clutch, and somefor motorcycles with a dry clutch.

JASO (Japanese Automobile Standard Organization) MB oils are beingwidely used in the world for four cycle gasoline engine of motorcycleswith a dry clutch, e.g. scooter. The MB oils have been formulated withMoDTC since it is essential to meet OEM's requirement of frictioncharacteristics and fuel economy. One such lubricant is described inJP2004099676.

SUMMARY OF THE INVENTION

In accordance with one embodiment of the present invention, there isprovided a MoDTC-free lubricating oil composition for motorcycles whichcomprises an engine and a clutch.

wherein the composition comprises:

-   -   (a) a major amount of an oil of lubricating viscosity,    -   (b) a molybdenum compound, and    -   (c) a salicylate detergent having a TBN 100-450 on active        basis.,

wherein the composition lubricates the engine but not the clutch.

In another embodiment, provided is a method for lubricating the engineof a motorcycle which comprises an engine and a clutch, with aMoDTC-free lubricating oil composition,

wherein the composition comprises:

-   -   (a) a major amount of an oil of lubricating viscosity,    -   (b) a molybdenum compound, and    -   (c) a salicylate detergent having a TBN 100-450 on active basis,        and

wherein the composition lubricates the engine but not the clutch.

In a further embodiment, disclosed is the use of a lubricating oilcomposition to lubricate the engine of a motorcycle which comprises anengine and a clutch, with a MoDTC-free lubricating oil composition,

wherein the composition comprises:

-   -   a. a major amount of an oil of lubricating viscosity,    -   b. a molybdenum compound, and    -   c. a salicylate detergent having a TBN 100-450 on active basis,        and wherein the composition lubricates the engine but not the        clutch.

In another embodiment, disclosed is the use of the lubricating oilcompositions above to lubricate four cycle gasoline engines ofmotorcycles equipped with a dry clutch.

Definitions:

The following terms will be used throughout the specification and willhave the following meanings unless otherwise indicated.

The term “a major amount” of a base oil refers to where the amount ofthe base oil is at least 40 wt. % of the lubricating oil composition. Insome embodiments, “a major amount” of a base oil refers to an amount ofthe base oil more than 50 wt. %, more than 60 wt. %, more than 70 wt. %,more than 80 wt. %, or more than 90 wt. % of the lubricating oilcomposition.

In the following description, all numbers disclosed herein areapproximate values, regardless whether the word “about” or “approximate”is used in connection therewith. They may vary by 1 percent, 2 percent,5 percent, or, sometimes, 10 to 20 percent.

The term “Total Base Number” or “TBN” refers to the level of alkalinityin an oil sample, which indicates the ability of the composition tocontinue to neutralize corrosive acids, in accordance with ASTM StandardNo. D2896 or equivalent procedure. The test measures the change inelectrical conductivity, and the results are expressed as mgKOH/g (theequivalent number of milligrams of KOH needed to neutralize 1 gram of aproduct). Therefore, a high TBN reflects strongly overbased productsand, as a result, a higher base reserve for neutralizing acids.

The term “NAO” refers to Normal Alpha Olefins.

The term “on an actives basis” indicates that only the activecomponent(s) of a particular additive are considered when determiningthe concentration or amount of that particular additive within theoverall motorcycle lubricating oil composition. Diluent oil in theadditive is excluded.

DETAILED DESCRIPTION OF THE INVENTION

Provided herein are lubricating oil compositions suitable formotorcycles that do not have a clutch lubricated by the same lubricant,e.g., with non-lubricated (“dry”) clutch plates. The compositions areMoDTC-free, but give low friction properties and show good fuel economyperformance.

Molybdenum Succinimide

The unsulfurized or sulfurized oxymolybdenum-containing compoundsemployed in the present invention ([component (b)] may be generallycharacterized as an oxymolybdenum complex of a basic nitrogen compound.Such molybdenum/sulfur complexes are known in the art and are described,for example, in U.S. Pat. No. 4,263,152 to King et al., the disclosureof which is hereby incorporated by reference.

The structure of the molybdenum compound employed in this invention arenot known with certainty; however, they are believed to be compounds inwhich molybdenum, whose valences are satisfied with atoms of oxygen orsulfur, is either complexed by, or the salt of, one or more nitrogenatoms of the basic nitrogen containing compound used in the preparationof these compositions.

The molybdenum compounds used to prepare the oxymolybdenum andoxymolybdenum/sulfur complexes employed in the present invention areacidic molybdenum compounds. By acidic is meant that the molybdenumcompounds will react with a basic nitrogen compound as measured by ASTMtest D-664 or D-2896 titration procedure. Typically, these molybdenumcompounds are hexavalent and are represented by the following compounds:molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdateand other alkaline metal molybdates and other molybdenum salts such ashydrogen salts, e.g., hydrogen sodium molybdate, MoOCl₄, MoO₂Br₂,Mo₂O₃Cl₆, molybdenum trioxide or similar acidic molybdenum compounds.Preferred acidic molybdenum compounds are molybdic acid, ammoniummolybdate, and alkali metal molybdates. Particularly preferred aremolybdic acid and ammonium molybdate.

The basic nitrogen compound used to prepare the oxymolybdenum complexeshave at least one basic nitrogen and are preferably oil-soluble. Typicalexamples of such compound are succinimides, carboxylic acid amides,hydrocarbyl monoamines, hydrocarbon polyamines. Mannich bases,phosphoramides, thiophosphoramides, phosphonamides, dispersant viscosityindex improvers, and mixtures thereof. Any of the nitrogen-containingcompounds may be after-treated with, e.g., boron, using procedures wellknown in the art so long as the compounds continue to contain basicnitrogen. These after-treatments are particularly applicable tosuccinimides and Mannich base compositions.

The mono and polysuccinimides that can be used to prepare the molybdenumcomplexes described herein are disclosed in numerous references and arewell known in the art. Certain fundamental types of succinimides and therelated materials encompassed by the term of art “succinimide” aretaught in U.S. Pat. Nos. 3,219,666; 3,172,892; and 3,272,746, thedisclosures of which are hereby incorporated by reference. The term“succinimide” is understood in the art to include many of the amide,imide, and amidine species which may also be formed. The predominantproduct however is a succinimide and this term has been generallyaccepted as meaning the product of a reaction of an alkenyl substitutedsuccinic acid or anhydride with a nitrogen-containing compound.Preferred succinimides, because of their commercial availability, arethose succinimides prepared from a hydrocarbyl succinic anhydride,wherein the hydrocarbyl group contains from about 24 to about 350 carbonatoms, and an ethylene amine, said ethylene amines being especiallycharacterized by ethylene diamine, diethylene triamine, triethylenetetramine, and tetraethylene pentamine. Particularly preferred are thosesuccinimides prepared from polyisobutenyl succinic anhydride of 70 to128 carbon atoms and tetraethylene pentamine or triethylene tetramine ormixtures thereof.

Also included within the term “succinimide” are the cooligomers of ahydrocarbyl succinic acid or anhydride and a poly secondary aminecontaining at least one tertiary amino nitrogen in addition to two ormore secondary amino groups. Ordinarily this composition has between1500 and 50000 average molecular weight. A typical compound would bethat prepared by reacting polyisobutenyl succinic anhydride and ethylenedipiperazine.

Carboxylic acid amide compounds are also suitable starting materials forpreparing the oxymolybdenum complexes employed in this invention.Typical of such compounds are those disclosed in U.S. Pat. No.3,405,064, the disclosure of which is hereby incorporated by reference.These compounds are ordinarily prepared by reacting a carboxylic acid oranhydride or ester thereof, having at least 12 to about 350 aliphaticcarbon atoms in the principal aliphatic chain and, if desired, havingsufficient pendant aliphatic groups to render the molecule oil solublewith an amine or a hydrocarbyl polyamine, such as an ethylene amine, togive a mono or polycarboxylic acid amide. Preferred are those amidesprepared from (1) a carboxylic acid of the formula R′COOH, where R′ isC₁₂₋₂₀ alkyl or a mixture of this acid with a polyisobutenyl carboxylicacid in which the polyisobutenyl group contains from about 72 to 128carbon atoms and (2) an ethylene amine, especially triethylene tetramineor tetraethylene pentamine or mixtures thereof.

Another class of compounds which are useful in this invention arehydrocarbyl monoamines and hydrocarbyl polyamines, preferably of thetype disclosed in U.S. Pat. No. 3,574,576, the disclosure of which ishereby incorporated by reference. The hydrocarbyl group, which ispreferably alkyl, or olefinic having one or two sites of unsaturation,usually contains from about 9 to 350, preferably from about 20 to 200carbon atoms. Particularly preferred hydrocarbyl polyamines are thosewhich are derived, e.g., by reacting polyisobutenyl chloride and apolyalkylene polyamine, such as an ethylene amine, e.g., ethylenediamine, diethylene triamine, tetraethylene pentamine,2-aminoethylpiperazine, 1,3-propylene diamine, 1,2-propylenediamine, andthe like.

Another class of compounds useful for supplying basic nitrogen are theMannich base compounds. These compounds are prepared from a phenol orC₉₋₂₀₀ alkylphenol, an aldehyde, such as formaldehyde or formaldehydeprecursor such as paraformaldehyde, and an amine compound. The amine maybe a mono or polyamine and typical compounds are prepared from analkylamine, such as methylamine or an ethylene amine, such as,diethylene triamine, or tetraethylene pentamine, and the like. Thephenolic material may be sulfurized and preferably is dodecylphenol or aC₈₀₋₁₀₀ alkylphenol. Typical Mannich bases which can be used in thisinvention are disclosed in U.S. Pat. Nos. 4,157,309 and 3,649,229;3,368,972; and 3,539,663, the disclosures of which are herebyincorporated by reference. The last referenced patent discloses Mannichbases prepared by reacting an alkylphenol having at least 50 carbonatoms, preferably 50 to 200 carbon atoms with formaldehyde and analkylene polyamine HN(ANH)_(n)H where A is a saturated divalent alkylhydrocarbon of from about 2 to 6 carbon atoms and n is from about 1-10and where the condensation product of said alkylene polyamine may befurther reacted with urea or thiourea. The utility of these Mannichbases as starting materials for preparing lubricating oil additives canoften be significantly improved by treating the Mannich base usingconventional techniques to introduce boron into the composition.

Another class of compounds useful for preparing the oxymolybdenumcomplexes employed in this invention are the phosphoramides andphosphonamides such as those disclosed in U.S. Pat. Nos. 3,909,430 and3,968,157, the disclosures of which are hereby incorporated byreference. These compounds may be prepared by forming a phosphoruscompound having at least one P—N bond. They can be prepared, forexample, by reacting phosphorus oxychloride with a hydrocarbyl diol inthe presence of a monoamine or by reacting phosphorus oxychloride with adifunctional secondary amine and a mono-functional amine.Thiophosphoramides can be prepared by reacting an unsaturatedhydrocarbon compound containing from about 2 to 450 or more carbonatoms, such as polyethylene, polyisobutylene, polypropylene, ethylene,1-hexene, 1,3-hexadiene, isobutylene, 4-methyl-1-pentene, and the like,with phosphorus pentasulfide and a nitrogen-containing compound asdefined above, particularly an alkylamine, alkyldiamine, alkylpolyamine,or an alkyleneamine, such as ethylene diamine, diethylenetriamine,triethylenetetramine, tetraethylenepentamine, and the like.

Another class of nitrogen-containing compounds useful in preparing themolybdenum complexes employed in this invention includes the so-calleddispersant viscosity index improvers (VI improvers). These VI improversare commonly prepared by functionalizing a hydrocarbon polymer,especially a polymer derived from ethylene and/or propylene, optionallycontaining additional units derived from one or more co-monomers such asalicyclic or aliphatic olefins or diolefins. The functionalization maybe carried out by a variety of processes which introduce a reactive siteor sites which usually has at least one oxygen atom on the polymer. Thepolymer is then contacted with a nitrogen-containing source to introducenitrogen-containing functional groups on the polymer backbone. Commonlyused nitrogen sources include any basic nitrogen compound especiallythose nitrogen-containing compounds and compositions described herein.Preferred nitrogen sources are alkylene amines, such as ethylene amines,alkyl amines, and Mannich bases.

Preferred basic nitrogen compounds for use in this invention aresuccinimides, carboxylic acid amides, and Mannich bases. More preferredare succinimides having an average molecular weight of 1000 or 1300 or2300 and mixtures thereof. Such succinimides can be post treated withboron or ethylene carbonate as known in the art.

The oxymolybdenum complexes of this invention can also be sulfurized.Representative sulfur sources for preparing the oxymolybdenum/sulfurcomplexes used in this invention are sulfur, hydrogen sulfide, sulfurmonochloride, sulfur dichloride, phosphorus pentasulfide, R″₂—S_(x)where R″ is hydrocarbyl, preferably C₁₋₄₀ alkyl, and x is at least 2,inorganic sulfides and polysulfides such as (NH₄)₂S_(y), where y is atleast 1, thioacetamide, thiourea, and mercaptans of the formula R″SHwhere R″ is as defined above. Also useful as sulfurizing agents aretraditional sulfur-containing antioxidants such as wax sulfides andpolysulfides, sulfurized olefins, sulfurized carboxylic and esters andsulfurized ester-olefins, and sulfurized alkylphenols and the metalsalts thereof.

The sulfurized fatty acid esters are prepared by reacting sulfur, sulfurmonochloride, and/or sulfur dichloride with an unsaturated fatty esterunder elevated temperatures. Typical esters include C₁-C₂₀ alkyl estersof C₈-C₂₄ unsaturated fatty acids, such as palmitoleic, oleic,ricinoleic, petroselinic, vaccenic, linoleic, linolenic, oleostearic,paranaric, tariric, gadoleic, arachidonic, cetoleic, etc. Particularlygood results have been obtained with mixed unsaturated fatty acidesters, such as are obtained from animal fats and vegetable oils, suchas tall oil, linseed oil, olive oil, castor oil, peanut oil, rape oil,fish oil, sperm oil, and so forth.

Exemplary fatty esters include lauryl tallate, methyl oleate, ethyloleate, lauryl oleate, cetyl oleate, cetyl linoleate, laurylricinoleate, oleyl linoleate, oleyl stearate, and alkyl glycerides.

Cross-sulfurized ester olefins, such as a sulfurized mixture of C₁₀-C₂₅olefins with fatty acid esters of C₁₀-C₂₅ fatty acids and C₁₀-C₂₅ alkylor alkenyl alcohols, wherein the fatty acid and/or the alcohol isunsaturated may also be used.

Sulfurized olefins are prepared by the reaction of the C₃-C₆ olefin or alow-molecular-weight polyolefin derived therefrom with asulfur-containing compound such as sulfur, sulfur monochloride, and/orsulfur dichloride.

Also useful are the aromatic and alkyl sulfides, such as dibenzylsulfide, dixylyl sulfide, dicetyl sulfide, diparaffin wax sulfide andpolysulfide, cracked wax-olefin sulfides and so forth. They can beprepared by treating the starting material, e.g., olefinicallyunsaturated compounds, with sulfur, sulfur monochloride, and sulfurdichloride. Particularly preferred are the paraffin wax thiomersdescribed in U.S. Pat. No. 2,346,156.

Sulfurized alkyl phenols and the metal salts thereof includecompositions such as sulfurized dodecylphenol and the calcium saltsthereof. The alkyl group ordinarily contains from about 9 to 300 carbonatoms. The metal salt may be preferably, a Group I or Group II salt,especially sodium, calcium, magnesium, or barium.

Preferred sulfur sources are sulfur, hydrogen sulfide, phosphoruspentasulfide, R′″₂S_(z) where R′″ is hydrocarbyl, preferably C₁-C₁₀alkyl, and z is at least 3, mercaptans wherein R′″ is C₁-C₁₀ alkyl,inorganic sulfides and polysulfides, thioacetamide, and thiourea. Mostpreferred sulfur sources are sulfur, hydrogen sulfide, phosphoruspentasulfide, and inorganic sulfides and polysulfides.

The polar promoter used in the preparation of the molybdenum complexesemployed in this invention is one which facilitates the interactionbetween the acidic molybdenum compound and the basic nitrogen compound.A wide variety of such promoters are well known to those skilled in theart. Typical promoters are 1,3-propanediol, 1,4-butane-diol, diethyleneglycol, butyl cellosolve, propylene glycol, 1,4-butyleneglycol, methylcarbitol, ethanolamine, diethanolamine, N-methyl-diethanol-amine,dimethyl formamide, N-methyl acetamide, dimethyl acetamide, methanol,ethylene glycol, dimethyl sulfoxide, hexamethyl phosphoramide,tetrahydrofuran and water. Preferred are water and ethylene glycol.Particularly preferred is water.

While ordinarily the polar promoter is separately added to the reactionmixture, it may also be present, particularly in the case of water, as acomponent of non-anhydrous starting materials or as waters of hydrationin the acidic molybdenum compound, such as (NH₄)₆Mo₇O₂₄.H₂O. Water mayalso be added as ammonium hydroxide.

A method for preparing the oxymolybdenum complexes used in thisinvention is to prepare a solution of the acidic molybdenum precursorand a polar promoter with a basic nitrogen-containing compound with orwithout diluent. The diluent is used, if necessary, to provide asuitable viscosity for easy stirring. Typical diluents are lubricatingoils and liquid compounds containing only carbon and hydrogen. Ifdesired, ammonium hydroxide may also be added to the reaction mixture toprovide a solution of ammonium molybdate. This reaction is carried outat a variety of temperatures, typically at or below the melting point ofthe mixture to reflux temperature. It is ordinarily carried out atatmospheric pressure although higher or lower pressures may be used ifdesired. This reaction mixture may optionally be treated with a sulfursource as defined above at a suitable pressure and temperature for thesulfur source to react with the acidic molybdenum and basic nitrogencompounds. In some cases, removal of water from the reaction mixture maybe desirable prior to completion of reaction with the sulfur source.

In a preferred and improved method for preparing the oxymolybdenumcomplexes, the reactor is agitated and heated at a temperature less thanor equal to about 120° C., preferably from about 70° C. to about 90° C.Molybdic oxide or other suitable molybdenum source is then charged tothe reactor and the temperature is maintained at a temperature less thanor equal to about 120° C., preferably at about 70° C. to about 90° C.,until the molybdenum is sufficiently reacted. Excess water is removedfrom the reaction mixture. Removal methods include but are not limitedto vacuum distillation or nitrogen stripping while maintaining thetemperature of the reactor at a temperature less than or equal to about120° C., preferably between about 70° C. to about 90° C. The temperatureduring the stripping process is held at a temperature less than or equalto about 120° C., to maintain the low color intensity of themolybdenum-containing composition. It is ordinarily carried out atatmospheric pressure although higher or lower pressures may be used. Thestripping step is typically carried out for a period of about 0.5 toabout 5 hours.

If desired, this product can be sulfurized by treating this reactionmixture with a sulfur source as defined above at a suitable pressure andtemperature, not to exceed about 120° C. for the sulfur source to reactwith the acidic molybdenum and basic nitrogen compounds. Thesulfurization step is typically carried out for a period of from about0.5 to about 5 hours and preferably from about 0.5 to about 2 hours. Insome cases, removal of the polar promoter (water) from the reactionmixture may be desirable prior to completion of reaction with the sulfursource.

The oxymolybdenum complex and oxymolybdenum/sulfur complex produced bysuch method is lighter in color (when compared to complexes prepared athigher temperatures) while maintaining good fuel economy, excellentoxidation inhibition, and anti-wear performance qualities. Color in thisinstance can be more visibly or more quantifiably using a UVspectrophotometer such as a Perkin-Elmer Lambda 18 UV-VisibleDouble-Beam Spectrophotometer. As used herein, this test recorded thevisible spectra of molybdenum compositions at a constant concentrationin an isooctane solvent. The spectra represent the absorbance intensityplotted versus the wavelength in nanometers. The spectra extend from thevisible region into the near infrared region of the electromagneticradiation (350 nanometers to 900 nanometers). In this test, the highlycolored samples showed increasingly higher absorbance at increasinglyhigher wavelengths at a constant molybdenum concentration. Thepreparation of the sample for color measurement comprises diluting themolybdenum-containing composition with isooctane to achieve a constantmolybdenum concentration of 0.00025 g molybdenum per gram of themolybdenum-containing composition/isooctane mixture. Prior to samplemeasurement the spectrophotometer is referenced by scanning air versusair. The UV visible visible spectrum from 350 nanometers to 900nanometers is obtained using a one centimeter path-length quartz cellversus an air reference. The spectra are offset corrected by selling the867 nanometer absorbance to zero. Then the absorbance of the sample isdetermined at 350 nanometers wavelength.

Characteristics of these new oxymolybdenum/sulfur complexes aredisclosed in U.S. patent application Ser. No. 10/159,446 filed May 31,2002, entitled REDUCED COLOR MOLYBDENUM-CONTAINING COMPITION AND AMETHOD OF MAKING SAME, incorporated herein by reference in its entirety.

In the reaction mixture, the ratio of molybdenum compound to basicnitrogen compound is not critical; however, as the amount of molybdenumwith respect to basic nitrogen increases, the filtration of the productbecomes more difficult. Since the molybdenum component probablyoligomerizes, it is advantageous to add as much molybdenum as can easilybe maintained in the composition. Usually, the reaction mixture willhave charged to it from about 0.01 to 2.00 atoms of molybdenum per basicnitrogen atom. Preferably from about 0.3 to 1.0, and most preferablyfrom about 0.4 to 0.7, atoms of molybdenum per atom of basic nitrogen isadded to the reaction mixture.

When optionally sulfurized, the sulfurized oxymolybdenum containingcompositions may be generally characterized as a sulfur/molybdenumcomplex of a basic nitrogen dispersant compound preferably with a sulfurto molybdenum weight ratio of from about (0.01 to 1.0) to 1 and morepreferably from about (0.05 to 0.5) to 1 and a nitrogen to molybdenumweight ratio of from about (1 to 10) to 1 and more preferably from about(2 to 5) to 1. For extremely low sulfur incorporation the sulfur tomolybdenum weight ratio can be from about (0.01 to 0.08) to 1.

The oxymolybdenum-containing complex comprises from about 0.02 to 10 wt% and preferably from about 0.1 to 2.0 wt %, based on the total weightof the lubricating oil composition.

In one embodiment, the molybdenum succinimide present in the lubricationoil is 0.1-5 wt %. In another embodiment, the molybdenum succinimidepresent in the lubrication oil is 0.1-2 wt %. In another embodiment, themolybdenum succinimide present in the lubrication oil is 0.1-1 wt %. Inanother embodiment, the molybdenum succinimide present in thelubrication oil is 0.5-2 wt %. In another embodiment, the molybdenumsuccinimide present in the lubrication oil is 0.1-2 wt %. In anotherembodiment, the molybdenum succinimide present in the lubrication oil is0.5-1 wt %.

Salicylate

In one embodiment, the lubricating oil composition disclosed hereincomprises a salicylate compound [component (c)]. In one embodiment, thesalicylate compound is a calcium alkylsalicylate detergent. The calciumalkylsalicylate detergent necessarily contained in the lubricating oilcomposition of the invention contains an organic acid calcium salt togive the lubricating oil composition containing the organic acid calciumsalt in an amount of 0.1 to 10 wt. %, preferably 0.2 to 7 wt. %, morepreferably 1.0 to 6 wt. %, and comprises an unsuifurized calciumalkylsalicylate detergent having a TBN of 100-450 on active basis. Inone embodiment, the calcium alkylsalicylate detergent has a TBN 100-400on active basis. In one embodiment, the calcium alkylsalicyaltedetergent has a TBN 100-350 on active basis. In one embodiment, thecalcium alkylsalicylate detergent has a TBN 150-400 on active basis. Inone embodiment, the calcium alkylsalicylate detergent has a TBN 150-350on active basis. In one embodiment, the calcium alkylsalicylatedetergent has a TBN 200-400 on active basis. In one embodiment, thecalcium alkylsalicylate detergent has a TBN 200-350 on active basis. Inone embodiment, the calcium alkylsalicylate detergent has a TBN 250-400on active basis. In one embodiment, the calcium alkylsalicylatedetergent has a TBN 250-350 on active basis.

The calcium alkylsalicylate detergent may have an alkyl group having10-40 carbon atoms, and the alkyl group may be derived fromnormal-alpha-olefins (NAO) or isomerized normal-alpha-olefins (NAO). Inone embodiment, the calcium alkylsalicylate detergent may be derivedfrom a C14-18 NAO. In another embodiment, the calcium alkylsalicylatedetergent is derived from a C20-28 NAO. In another embodiment, thecalcium alkylsalicylate detergent is derived from a C20-24 isomerizedNAO.

The unsulfurized calcium alkylsalicylate detergent preferably is acalcium alkylsalicylate prepared from an alkyl phenol (which is preparedfrom α-olefin having the desired carbon atom number and phenol) by wayof Kolbe-Schmitt reaction. Generally, an overbased calcium salicylatewhich is obtained by way of the carbonation process using slaked limeand carbon dioxide gas for overbasing is used as the calcium salicylatedetergent.

Otherwise, the calcium alkylsalicylate can he directly produced bycarbonizing an alkylphenol calcium salt obtained by directneutralization.

In addition to the heretofore described metal-containing detergents, asmall amount of sulfonates such as alkali metal salts or alkaline earthmetal salts of petroleum sulfonic acid, alkylbenzenesulfonic acid oralkyltoluenesulfonic acid can be employed in combination with thealkylsalicylate detergent.

A sulfurized phenate which has been used for the conventional engineoils is an alkali metal salt or an alkaline earth metal salt of asulfurized alkylphenol. Typically, calcium salt and magnesium salt areemployed. The sulfurized phenate shows high thermal stability butgenerally has a high sulfur content such as approx. 3 wt. % or more,which is brought about by the sulfurization reaction. In the invention,a small amount of the sulfurized phenate may be employed in combinationwith the alkylsalicylate detergent.

In one embodiment, the calcium alkylsalicylate is 0.1-10 wt %. Inanother embodiment, the calcium alkylsalicylate is 0.5-10 wt %. Inanother embodiment, the calcium alkylsalicylate is 1-10 wt %. In anotherembodiment, the calcium alkylsalicylate is 2-10 wt %. In anotherembodiment, the calcium alkylsalicylate is 2-6wt %.

The Oil of Lubricating Viscosity

The lubricating oil compositions disclosed herein generally comprise atleast one oil of lubricating viscosity. Any base oil known to a skilledartisan can be used as the oil of lubricating viscosity disclosedherein. Some base oils suitable for preparing the lubricating oilcompositions have been described in Mortier et al., “Chemistry andTechnology of Lubricants,” 2nd Edition, London, Springer, Chapters 1 and2 (1996); and A. Sequeria, Jr., “Lubricant Base Oil and Wax Processing,”New York, Marcel Decker, Chapter 6, (1994); and D. V. Brock, LubricationEngineering, Vol. 43, pages 184-5, (1987), all of which are incorporatedherein by reference. Generally, the amount of the base oil in thelubricating Oil composition may be from about 70 to about 99.5 wt. %,based on the total weight of the lubricating oil composition. In someembodiments, the amount of the base oil in the lubricating oilcomposition is from about 75 to about 99 wt. %, from about 80 to about98.5 wt. %, or from about 80 to about 98 wt. %, based on the totalweight of the lubricating oil composition.

In certain embodiments, the base oil is or comprises any natural orsynthetic lubricating base oil fraction. Some non-limiting examples ofsynthetic oils include oils, such as polyalphaolefins or PAOs, preparedfrom the polymerization of at least one alpha-olefin, such as ethylene,or from hydrocarbon synthesis procedures using carbon monoxide andhydrogen gases, such as the Fisher-Tropsch process. In certainembodiments, the base oil comprises less than about 10 wt. % of one ormore heavy fractions, based on the total weight of the base oil. A heavyfraction refers to a lube oil fraction having a viscosity of at leastabout 20 cSt at 100° C. In certain embodiments, the heavy fraction has aviscosity of at least about 25 cSt or at least about 30 cSt at 100° C.In further embodiments, the amount of the one or more heavy fractions inthe base oil is less than about 10 wt. %, less than about 5 wt. %, lessthan about 2.5 wt. less than about 1 wt. %, or less than about 0.1 wt.%, based on the total weight of the base oil. In still furtherembodiments, the base oil comprises no heavy fraction.

In certain embodiments, the lubricating oil compositions comprise amajor amount of a base oil of lubricating viscosity. In someembodiments, the base oil has a kinematic viscosity at 100° C. fromabout 2.5 centistokes (cSt) to about 20 cSt, from about 4 centistokes(cSt) to about 20 cSt, or from about 5 cSt to about 16 cSt. Thekinematic viscosity of the base oils or the lubricating oil compositionsdisclosed herein can be measured according to ASTM D 445, which isincorporated herein by reference.

In other embodiments, the base oil is or comprises a base stock or blendof base stocks. In further embodiments, the base stocks are manufacturedusing a variety of different processes including, but not limited to,distillation, solvent refining, hydrogen processing, oligomerization,esterification, and rerefining. In some embodiments, the base stockscomprise a rerefined stock. In further embodiments, the rerefined stockshall be substantially free from materials introduced throughmanufacturing, contamination, or previous use.

In some embodiments, the base oil comprises one or more of the basestocks in one or more of Groups I-V as specified in the AmericanPetroleum Institute (API) Publication 1509, Fourteen Edition, December1996 (i.e., API Base Oil Interchangeability Guidelines for Passenger CarMotor Oils and Diesel Engine Oils), which is incorporated herein byreference. The API guideline defines a base stock as a lubricantcomponent that may be manufactured using a variety of differentprocesses. Groups I, II and III base stocks are mineral oils, each withspecific ranges of the amount of saturates, sulfur content and viscosityindex. Group IV base stocks are polyalphaolefins (PAO). Group V basestocks include all other base stocks not included in Group I, II, III,or IV.

In some embodiments, the base oil comprises one or more of the basestocks in Group I, II, III, IV, V or a combination thereof. In otherembodiments, the base oil comprises one or more of the base stocks inGroup II, III, IV or a combination thereof. In further embodiments, thebase oil comprises one or more of the base stocks in Group II, III, IVor a combination thereof wherein the base oil has a kinematic viscosityfrom about 2.5 centistokes (cSt) to about 20 cSt, from about 4 cSt toabout 20 cSt, or from about 5 cSt to about 16 cSt at 100° C.

The base oil may be selected from the group consisting of natural oilsof lubricating viscosity, synthetic oils of lubricating viscosity andmixtures thereof. In some embodiments, the base oil includes base stocksobtained by isomerization of synthetic wax and slack wax, as well ashydrocrackate base stocks produced by hydrocracking (rather than solventextracting) the aromatic and polar components of the crude. In otherembodiments, the base oil of lubricating viscosity includes naturaloils, such as animal oils, vegetable oils, mineral oils (e.g., liquidpetroleum oils and solvent treated or acid-treated mineral oils of theparaffinic, naphthenic or mixed paraffinic-naphthenic types), oilsderived from coal or shale, and combinations thereof. Some non-limitingexamples of animal oils include bone oil, lanolin, fish oil, lard oil,dolphin oil, seal oil, shark oil, tallow oil, and whale oil. Somenon-limiting examples of vegetable oils include castor oil, olive oil,peanut oil, rapeseed oil, corn oil, sesame oil, cottonseed oil, soybeanoil, sunflower oil, safflower oil, hemp oil, linseed oil, tung oil,oiticica oil, jojoba oil, and meadow foam oil. Such oils may bepartially or fully hydrogenated.

In some embodiments, the synthetic oils of lubricating viscosity includehydrocarbon oils and halo-substituted hydrocarbon oils such aspolymerized and inter-polymerized olefins, alkylbenzenes, polyphenyls,alkylated diphenyl ethers, alkylated diphenyl sulfides, as well as theirderivatives, analogues and homologues thereof, and the like. In otherembodiments, the synthetic oils include alkylene oxide polymers,interpolymers, copolymers and derivatives thereof wherein the terminalhydroxyl groups can be modified by esterification, etherification, andthe like. In further embodiments, the synthetic oils include the estersof dicarboxylic acids with a variety of alcohols. In certainembodiments, the synthetic oils include esters made from C₅ to C₁₂monocarboxylic acids and polyols and polyol ethers. In furtherembodiments, the synthetic oils include tri-alkyl phosphate ester oils,such as tri-n-butyl phosphate and tri-iso-butyl phosphate.

In some embodiments, the synthetic oils of lubricating viscosity includesilicon-based oils (such as the polyakyl-, polyaryl-, polyalkoxy-,polyaryloxy-siloxane oils and silicate oils). In other embodiments, thesynthetic oils include liquid esters of phosphorus-containing acids,polymeric tetrahydrofurans, polyalphaolefins, and the like.

Base oil derived from the hydroisomerization of wax may also be used,either alone or in combination with the aforesaid natural and/orsynthetic base oil. Such wax isomerate oil is produced by thehydroisomerization of natural or synthetic waxes or mixtures thereofover a hydroisomerization catalyst.

In further embodiments, the base oil comprises a poly-alpha-olefin(PAO). In general, the poly-alpha-olefins may be derived from analpha-olefin having from about 2 to about 30, from about 4 to about 20,or from about 6 to about 16 carbon atoms. Non-limiting examples ofsuitable poly-alpha-olefins include those derived from octene, decene,mixtures thereof, and the like. These poly-alpha-olefins may have aviscosity from about 2 to about 15, from about 3 to about 12, or fromabout 4 to about 8 centistokes at 100° C. In some instances, thepoly-alpha-olefins may be used together with other base oils such asmineral oils.

In further embodiments, the base oil comprises a polyalkylene glycol ora polyalkylene glycol derivative, where the terminal hydroxyl groups ofthe polyalkylene glycol may be modified by esterification,etherification, acetylation and the like. Non-limiting examples ofsuitable polyalkylene glycols include polyethylene glycol, polypropyleneglycol, polyisopropylene glycol, and combinations thereof. Non-limitingexamples of suitable polyalkylene glycol derivatives include ethers ofpolyalkylene glycols (e.g., methyl ether of polyisopropylene glycol,diphenyl ether of polyethylene glycol, diethyl ether of polypropyleneglycol, etc.), mono- and polycarboxylic esters of polyalkylene glycols,and combinations thereof. In some instances, the polyalkylene glycol orpolyalkylene glycol derivative may be used together with other base oilssuch as poly-alpha-olefins and mineral oils.

In further embodiments, the base oil comprises any of the esters ofdicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinicacids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid,sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonicacid, alkyl malonic acids, alkenyl malonic acids, and the like) with avariety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecylalcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycolmonoether, propylene glycol, and the like). Non-limiting examples ofthese esters include dibutyl adipate, di(2-ethylhexyl) sebacate,di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecylazelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the2-ethylhexyl diester of linoleic acid dimer, and the like.

In further embodiments, the base oil comprises a hydrocarbon prepared bythe Fischer-Tropsch process. The Fischer-Tropsch process prepareshydrocarbons from gases containing hydrogen and carbon monoxide using aFischer-Tropsch catalyst. These hydrocarbons may require furtherprocessing in order to be useful as base oils. For example, thehydrocarbons may be dewaxed, hydroisomerized, and/or hydrocracked usingprocesses known to a person of ordinary skill in the art.

In further embodiments, the base oil comprises an unrefined oil, arefined oil, a rerefined oil, or a mixture thereof. Unrefined oils arethose obtained directly from a natural or synthetic source withoutfurther purification treatment. Non-limiting examples of unrefined oilsinclude shale oils obtained directly from retorting operations,petroleum oils obtained directly from primary distillation, and esteroils obtained directly from an esterification process and used withoutfurther treatment. Refined oils are similar to the unrefined oils exceptthe former have been further treated by one or more purificationprocesses to improve one or more properties. Many such purificationprocesses are known to those skilled in the art such as solventextraction, secondary distillation, acid or base extraction, filtration,percolation, and the like. Rerefined oils are obtained by applying torefined oils processes similar to those used to obtain refined oils.Such rerefined oils are also known as reclaimed or reprocessed oils andoften are additionally treated by processes directed to removal of spentadditives and oil breakdown products.

Other Additives

Optionally, the lubricating oil composition may further comprise alleast an additive or a modifier (hereinafter designated as “additive”)that can impart or improve any desirable property of the lubricating oilcomposition. Any additive known to a person of ordinary skill in the artmay be used in the lubricating oil compositions disclosed herein. Somesuitable additives have been described in Mortier et al., “Chemistry andTechnology of Lubricants,” 2nd Edition, London, Springer, (1996); andLeslie R. Rudnick, “Lubricant Additives: Chemistry and Applications,”New York, Marcel Dekker (2003), both of which are incorporated herein byreference. In some embodiments, the additive can be selected from thegroup consisting of antioxidants, antiwear agents, detergents, rustinhibitors, demulsifiers, friction modifiers, multi-functionaladditives, viscosity index improvers, pour point depressants, foaminhibitors, metal deactivators, dispersants, corrosion inhibitors,lubricity improvers, thermal stability improvers, anti-haze additives,icing inhibitors, dyes, markers, static dissipaters, biocides andcombinations thereof. In general, the concentration of each of theadditives in the lubricating oil composition, when used, may range fromabout 0.001 wt. % to about 10 wt. %, from about 0.01 wt. % to about 5wt. %, or from about 0.1 wt % to about 2.5 wt. %, based on the totalweight of the lubricating oil composition. Further, the total amount ofthe additives in the lubricating oil composition may range from about0.001 wt. % to about 20 wt. %, from about 0.01 wt. % to about 10 wt. %,or from about 0.1 wt. % to about 5 wt. %, based on the total weight ofthe lubricating oil composition.

Dispersants

In one embodiment, the lubricating oil composition disclosed hereincomprises an ashless dispersant which can be an alkenyl succinimide, analkyl succinimide, or a derivative thereof, in which the alkenyl groupand alkyl group can be derived from polyolefin. The ashless dispersantis incorporated into the lubricating oil composition in an amount of0.01 to 0.3 wt. % in terms of the nitrogen content. The percent is givenper the amount of the lubricating oil composition. A representativesuccinimide can be obtained by the reaction between succinic anhydridehaving a substituent group of a high molecular weight alkenyl or alkylwith a polyalkylene polyamine having a mean nitrogen atom number of 4 to10, preferably 5 to 7. The high molecular weight alkenyl or alkyl ispreferably derived from polybutene having a number average molecularweight of approximately 900 to 3,000, 900 to 2300, 900 to 1100, or 1100to 2300.

In the process for producing a polybutenyl succinic anhydride by thereaction of polybutene and maleic anhydride, a chlorination procedure isgenerally employed. However, the chlorination procedure gives remainingchlorine in the product, and hence the finally produced succinimideinevitably contains a large amount (such as approximately 2,000 to 3,000ppm) of the emigrated chlorine. In contrast, the thermal reaction usingno chlorine gives a final product having an extremely small chlorinecontent (such as 0 to 30 ppm). Therefore, the succinimide derived from apolyisobutenyl succinimide obtained by the thermal reaction can befavorably employed for formulating a lubricating oil composition havinglow chlorine content such as 0 to 30 wt. ppm. The succinimide can bepost-treated with boric acid, a boron-containing compound, alcohol,aldehyde, ketone, alkylphenol, cyclic carbonate or an organic acid.Preferred is a borated alkenyl- (or alkyl-) succinimide which isobtained by post-treatment with boric acid or a boron-containingcompound, and which shows high thermal stability and high oxidationstability.

In one embodiment, the lubricating oil composition comprises asuccinimide. In another embodiment, the lubricating oil compositioncomprises a bissucinimide. In another embodiment, the lubricating oilcomposition comprises a borated bissuccinimide. In another embodiment,the lubricating oil composition comprises a mixture of borated andnon-borated bissucinimide.

Antioxidants

The lubricating oil composition of the present invention can contain oneor more antioxidants that can reduce or prevent the oxidation of thebase oil. Any antioxidant known by a person of ordinary skill in the artmay be used in the lubricating oil composition. Non-limiting examples ofsuitable antioxidants include amine-based antioxidants (e.g., alkyldiphenylamines such as bis-nonylated diphenylamine, bis-octylateddiphenylamine, and octylated/butylated diphenylamine,phenyl-α-naphthylamine, alkyl or arylalkyl substitutedphenyl-α-naphthylamine, alkylated p-phenylene diamines,tetramethyl-diaminodiphenylamine and the like), phenolic antioxidants(e.g., 2-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol,2,4,6-tri-tert-butylphenol, 2,6-di-tert-butyl-p-cresol,2,6-di-tert-butylphenol, 4,4′-methylenebis-(2,6-di-tert-butylphenol),4,4′-thiobis(6-di-tert-butyl-o-cresol) and the like), sulfur-basedantioxidants (e.g., dilauryl-3,3′-thiodipropionate, sulfurized phenolicantioxidants and the like), phosphorous-based antioxidants (e.g.,phosphites and the like), zinc dithiophosphate, oil-soluble coppercompounds and combinations thereof. The amount of the antioxidant mayvary from about 0.01 wt. % to about 10 wt. %, from about 0.05 wt. % toabout 5 wt. %, or from about 0.1 wt. % to about 3 wt. %, based on thetotal weight of the lubricating oil composition.

Wear Inhibitors

The lubricating oil composition of the present invention can contain oneor more anti-wear agents that can reduce friction and excessive wear.Any anti-wear agent known by a person of ordinary skill in the art maybe used in the lubricating oil composition. Non-limiting examples ofsuitable anti-wear agents include zinc dithiophosphate, metal (e.g., Pb,Sb, Mo and the like) salts of dithiophosphates, metal (e.g., Zn, Pb, Sb,Mo and the like) salts of dithiocarbamates, metal (e.g., Zn, Pb, Sb andthe like) salts of fatty acids, boron compounds, phosphate esters,phosphite esters, amine salts of phosphoric acid esters orthiophosphoric acid esters, reaction products of dicyclopentadiene andthiophosphoric acids and combinations thereof. The amount of theanti-wear agent may vary from about 0.01 wt. % to about 5 wt. %, fromabout 0.05 wt. % to about 3 wt. %, or from about 0.1 wt. % to about 1wt. %, based on the total weight of the lubricating oil composition.

In certain embodiments, the anti-wear agent is or comprises adihydrocarbyl dithiophosphate metal salt, such as zinc dialkyldithiophosphate compounds. The metal of the dihydrocarbyldithiophosphate metal salt may be an alkali or alkaline earth metal, oraluminum, lead, tin, molybdenum, manganese, nickel or copper. In someembodiments, the metal is zinc. In other embodiments, the alkyl group ofthe dihydrocarbyl dithiophosphate metal salt has from about 3 to about22 carbon atoms, from about 3 to about 18 carbon atoms, from about 3 toabout 12 carbon atoms, or from about 3 to about 8 carbon atoms. Infurther embodiments, the alkyl group is linear or branched.

The amount of the dihydrocarbyl dithiophosphate metal salt including thezinc dialkyl dithiophosphate salts in the lubricating oil compositiondisclosed herein is measured by its phosphorus content. In someembodiments, the phosphorus content of the lubricating oil compositiondisclosed herein is from about 0.01 wt. % to about 0.14 wt., based onthe total weight of the lubricating oil composition.

Foam Inhibitors

The lubricating oil composition of the present invention can contain oneor more foam inhibitors or anti-foam inhibitors that can break up foamsin oils. Any foam inhibitor or anti-foam known by a person of ordinaryskill in the art may be used in the lubricating oil composition.Non-limiting examples of suitable foam inhibitors or anti-foaminhibitors include silicone oils or polydimethylsiloxanes,fluorosilicones, alkoxylated aliphatic acids, polyethers (e.g.,polyethylene glycols), branched polyvinyl ethers, alkyl acrylatepolymers, alkyl methacrylate polymers, polyalkoxyamines and combinationsthereof. In some embodiments, the foam inhibitors or anti-foaminhibitors comprises glycerol monostearate, polyglycol palmitate, atrialkyl monothiophosphate, an ester of sulfonated ricinoleic acid,benzoylacetone, methyl salicylate, glycerol monooleate, or glyceroldioleate. The amount of the foam inhibitors or anti-foam inhibitors mayvary from about 0.001 wt. % to about 5 wt. %, from about 0.05 wt. % toabout 3 wt. %, or from about 0.1 wt. % to about 1 wt. %, based on thetotal weight of the lubricating oil composition.

Pour Point Depressants

The lubricating oil composition of the present invention can contain oneor more pour point depressants that can lower the pour point of thelubricating oil composition. Any pour point depressant known by a personof ordinary skill in the art may be used in the lubricating oilcomposition. Non-limiting examples of suitable pour point depressantsinclude polymethacrylates, alkyl acrylate polymers, alkyl methacrylatepolymers, di(tetra-paraffin phenol)phthalate, condensates oftetra-paraffin phenol, condensates of a chlorinated paraffin withnaphthalene and combinations thereof. In some embodiments, the pourpoint depressant comprises an ethylene-vinyl acetate copolymer, acondensate of chlorinated paraffin and phenol, polyalkyl styrene or thelike. The amount of the pour point depressant may vary from about 0.01wt. % to about 10 wt. %, from about 0.05 wt. % to about 5 wt. %, or fromabout 0.1 wt. % to about 3 wt. %, based on the total weight of thelubricating oil composition.

Demulsifiers

In one embodiment, the lubricating oil composition of the presentinvention does not contain one or more demulsifiers. In anotherembodiment, the lubricating oil composition of the present invention cancontain one or more demulsifiers that can promote oil-water separationin lubricating oil compositions that are exposed to water or steam. Anydemulsifier known by a person of ordinary skill in the art may be usedin the lubricating oil composition. Non-limiting examples of suitabledemulsifiers include anionic surfactants (e.g., alkyl-naphthalenesulfonates, alkyl benzene sulfonates and the like), nonionic alkoxylatedalkyl phenol resins, polymers of alkylene oxides (e.g., polyethyleneoxide, polypropylene oxide, block copolymers of ethylene oxide,propylene oxide and the like), esters of oil soluble acids,polyoxyethylene sorbitan ester and combinations thereof. The amount ofthe demulsifier may vary from about 0.01 wt. % to about 10 wt. %, fromabout 0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to about 3wt. %, based on the total weight of the lubricating oil composition.

Corrosion Inhibitors

The lubricating oil composition of the present invention can contain oneor more corrosion inhibitors that can reduce corrosion. Any corrosioninhibitor known by a person of ordinary skill in the art may be used inthe lubricating oil composition. Non-limiting examples of suitablecorrosion inhibitor include half esters or amides of dodecylsuccinicacid, phosphate esters, thiophosphates, alkyl imidazolines, sarcosinesand combinations thereof. The amount of the corrosion inhibitor may varyfrom about 0.01 wt. % to about 5 wt. %, from about 0.05 wt. % to about 3wt. %, or from about 0.1 wt. % to about 1 wt. %, based on the totalweight of the lubricating oil composition.

Extreme Pressure Agents

The lubricating oil composition of the present invention can contain oneor more extreme pressure (EP) agents that can prevent sliding metalsurfaces from seizing under conditions of extreme pressure. Any extremepressure agent known by a person of ordinary skill in the art may beused in the lubricating oil composition. Generally, the extreme pressureagent is a compound that can combine chemically with a metal to form asurface film that prevents the welding of asperities in opposing metalsurfaces under high loads. Non-limiting examples of suitable extremepressure agents include sulfurized animal or vegetable fats or oils,sulfurized animal or vegetable fatty acid esters, fully or partiallyesterified esters of trivalent or pentavalent acids of phosphorus,sulfurized olefins, dihydrocarbyl polysulfides, sulfurized Diels-Alderadducts, sulfurized dicyclopentadiene, sulfurized or co-sulfurizedmixtures of fatty acid esters and monounsaturated olefins, co-sulfurizedblends of fatty acid, fatty acid ester and alpha-olefin,functionally-substituted dihydrocarbyl polysulfides, thia-aldehydes,thia-ketones, epithio compounds, sulfur-containing acetal derivatives,co-sulfurized blends of terpene and acyclic olefins, and polysulfideolefin products, amine salts of phosphoric acid esters or thiophosphoricacid esters and combinations thereof. The amount of the extreme pressureagent may vary from about 0.01 wt. % to about 5 wt. %, from about 0.05wt. % to about 3 wt. %, or from about 0.1 wt. % to about 1 wt. %, basedon the total weight of the lubricating oil composition.

Rust Inhibitors

The lubricating oil composition of the present invention can contain oneor more rust inhibitors that can inhibit the corrosion of ferrous metalsurfaces. Any rust inhibitor known by a person of ordinary skill in theart may be used in the lubricating oil composition. Non-limitingexamples of suitable rust inhibitors include nonionic polyoxyalkyleneagents, e.g., polyoxyethylene lauryl ether, polyoxyethylene higheralcohol ether, polyoxyethylene nonylphenyl ether, polyoxyethyleneoctylphenyl ether, polyoxyethylene octyl stearyl ether, polyoxyethyleneoleyl ether, polyoxyethylene sorbitol monostearate, polyoxyethylenesorbitol monooleate, and polyethylene glycol monooleate; stearic acidand other fatty acids; dicarboxylic acids; metal soaps; fatty acid aminesalts; metal salts of heavy sulfonic acid; partial carboxylic acid esterof polyhydric alcohol; phosphoric esters; (short-chain) alkenyl succinicacids; partial esters thereof and nitrogen-containing derivativesthereof; synthetic alkarylsulfonates, e.g., metal dinonylnaphthalenesulfonates; and the like and mixtures thereof. The amount of the rustinhibitor may vary from about 0.01 wt. % to about 10 wt. %, from about0.05 wt. % to about 5 wt. %, or from about 0.1 wt. % to about 3 wt. %,based on the total weight of the lubricating oil composition.

The lubricating oil composition of the present invention can contain oneor more metal deactivators. Non-limiting examples of suitable metaldeactivators include disalicylidene propylenediamine, triazolederivatives, thiadiazole derivatives, and mercaptobenzimidazoles.

VII

The lubricating oil composition of the present invention can contain oneor more viscosity index improvers. Non-limiting examples of suitableviscosity index improvers include, but are not limited to, olefincopolymers, such as ethylene-propylene copolymers, styrene-isoprenecopolymers, hydrated styrene-isoprene copolymers, polybutene,polyisobutylene, polymethacrylates, vinylpyrrolidone and methacrylatecopolymers and dispersant type viscosity index improvers. Theseviscosity modifiers can optionally be grafted with grafting materialssuch as, for example, maleic anhydride, and the grafted material can bereacted with, for example, amines, amides, nitrogen-containingheterocyclic compounds or alcohol, to form multifunctional viscositymodifiers (dispersant-viscosity modifiers). Other examples of viscositymodifiers include star polymers (e.g., a star polymer comprisingisoprene/styrene/isoprene triblock). Yet other examples of viscositymodifiers include poly alkyl(meth)acrylates of low Brookfield viscosityand high shear stability, functionalized poly alkyl(meth)acrylates withdispersant properties of high Brookfield viscosity and high shearstability, polyisobutylene having a weight average molecular weightranging from 700 to 2,500 Daltons and mixtures thereof. The amount ofthe viscosity index improvers may vary from about 0.01 wt. % to about 25wt. %, from about 0.05 wt. % to about 20 wt. %, or from about 0.3 wt. %to about 15 wt. %, based on the total weight of the lubricating oilcomposition.

Metal Deactivators

In some embodiments, the lubricating oil composition comprises at leasta metal deactivator. Some non-limiting examples of suitable metaldeactivators include disalicylidene propylenediamine, triazolederivatives, thiadiazole derivatives, and mercaptobenzimidazoles.

The additives disclosed herein may be in the form of an additiveconcentrate having more than one additive. The additive concentrate maycomprise a suitable diluent, such as a hydrocarbon oil of suitableviscosity. Such diluent can be selected from the group consisting ofnatural oils (e.g., mineral oils), synthetic oils and combinationsthereof. Some non-limiting examples of the mineral oils includeparaffin-based oils, naphthenic-based oils, asphaltic-based oils andcombinations thereof. Some non-limiting examples of the synthetic baseoils include polyolefin oils (especially hydrogenated alpha-olefinoligomers), alkylated aromatic, polyalkylene oxides, aromatic ethers,and carboxylate esters (especially diester oils) and combinationsthereof. In some embodiments, the diluent is a light hydrocarbon oil,both natural or synthetic. Generally, the diluent oil can have aviscosity from about 13 centistokes to about 35 centistokes at 40° C.

Generally, it is desired that the diluent readily solubilizes thelubricating oil soluble additive of the invention and provides an oiladditive concentrate that is readily soluble in the lubricant base oilstocks or fuels. In addition, it is desired that the diluent notintroduce any undesirable characteristics, including, for example, highvolatility, high viscosity, and impurities such as heteroatoms, to thelubricant base oil stocks and thus, ultimately to the finished lubricantor fuel.

The present invention further provides an oil soluble additiveconcentrate composition comprising an inert diluent and from 2.0% to 90%by weight, preferably 10% to 50% by weight based on the totalconcentrate, of an oil soluble additive composition according to thepresent invention.

The following examples are presented to exemplify embodiments of theinvention but are not intended to limit the invention to the specificembodiments set forth. Unless indicated to the contrary, all parts andpercentages are by weight. All numerical values are approximate. Whennumerical ranges are given, it should be understood that embodimentsoutside the stated ranges may still fall within the scope of theinvention. Specific details described in each example should not beconstrued as necessary features of the invention.

EXAMPLES

The following examples are intended for illustrative purposes only anddo not limit in any way the scope of the present invention.

The lubricating oil compositions for evaluating their performances wereprepared from the below-mentioned additives. All the lubricating oilcompositions were prepared to have a viscosity grade (SAE viscositygrade) of 10W-30.

Salicylate A: Ca salicylate having TBN of 280 on an active basis.

Salicylate B: Ca salicylate having TBN of 300 on an active basis.

Sulfonate: An oil concentrate of Ca sulfonate.

Phenate: An oil concentrate of Ca phenate.

Additionally, each of the examples contain 7.1 wt. % primary ZnDTP, 7.1wt. % secondary ZnDTP, 0.5 wt. % amine antioxidant, and 50 wt. ppm offoam inhibitor.

The lubricating oil compositions were evaluated according to the HighFrequency Reciprocating Rig (HFRR) Evaluation and JASCO T903:2011 asdescribed below.

Friction Performance

[High Frequency Reciprocating Rig (HFRR) Evaluation]

The friction coefficient was determined in terms of a metal-metalfriction coefficient.

The HFRR test rig is an industry recognized test for determininglubricant performance using a tribometer. The PCS instrument uses anelectromagnetic vibrator to oscillate a specimen (the ball) over a smallamplitude while pressing it against a fixed specimen (a flat disk). Theamplitude and frequency of the oscillation and the load are variable.The frictional force between the ball and flat disk and the electricalcontact resistance (ECR) are measured. The flat, stationary specimen isheld in a bath to which the lubricating oil is added, and can be heated.For this test, the tribometer was set up to run at >50 Hz for >60minutes, using 6 mm ball on flat specimens of 52100 steel. The load was1.0 kg and the temperature was 100° C. In this test, a smallercoefficient of friction corresponds to a more effective lubricatingfriction modifier additive. The HFRR friction performance data arepresented in Table 2.

JASO T903:2011 Procedure:

The lubricant compositions were subjected to a clutch system frictiontest as described in JASO T903:2011, The test evaluates three mainclutch parameters: static friction, relating to clutch slip; dynamicfriction, relating to clutch feel/uptake; and stop time, relating tosynchronization time. A clutch performance index is then assigned to thelubricating composition, which can be classified as JASO MA, JASO MA1,or JASO MA2 (high friction, suitable for wet clutch applications), orJASO MB (low friction, more suitable for dry clutch applications).

For a lubricating composition to claim JASO MB performance, all threeindices must fall within the values specified for the MB category, ortwo indices must fall within the values specified for the MB categoryand one within the values specified for the MA category, or one indexmust fall within the values specified for the MB category and two withinthe values specified for the MA category, as set forth below in Table 1.

TABLE 1 Parameter Index JASO MA JASO MA2 JASO MA1 JASO MB Dynamic DFI1.30 ≤ DFI < 2.50 1.85 ≤ DFI < 2.50 1.30 ≤ DFI < 1.85 0.5 ≤ DFI < 1.30Friction Index Static SFI 1.25 ≤ SFI < 2.50 1.70 ≤ SFI < 2.50 1.25 ≤ SFI< 1.70 0.5 ≤ SFI < 1.25 Friction Index Stop Time STI 1.45 ≤ STI < 2.501.85 ≤ STI < 2.50 1.45 ≤ STI < 1.85 0.5 ≤ STI < 1.45 Index

The JASO T903:2011 clutch performance data are presented in Table 2.

TABLE 2 Examples> 1 2 3 4 5 6 7 8 Comp A B C D Dispersant A 1.25 1.251.25 1.25 1.25 — 1.25 1.25 — — — 1.25 Dispersant B 1.25 1.25 1.25 1.251.25 — 1.25 1.25 2.5 2.5 2.5 1.25 Salicylate A 2.88 — 2.88 2.88 — — 2.885.76 — — — — Salicylate B — 2.88 — — 3.52 3.52 — — — — — — Molybdenum0.8 0.8 0.5 1.0 0.8 0.8 0.8 0.8 — — 0.8 0.8 Succinimide Phenate 0.420.42 0.42 0.42 — 2.3 — 0.21 2.3 — 2.3 2.3 Sulfonate — — — — — — 0.25 — —1.37 — — HFRR Friction 0.062 0.062 0.071 0.062 0.059 0.098 0.079 0.1070.151 0.136 0.113 0.09 Coefficient JASO MB MB MB MB MB MB MB MB MA/ MAMA/ MA/ Classification MA2 MA2 MA2 DFI 1.71 1.63 1.97 1.83 1.79 1.471.87 1.77 2.06 2.00 2.10 2.00 SFI 0.50 0.50 1.16 1.16 0.53 0.80 0.910.69 2.27 1.45 2.38 2.27 STI 1.57 1.48 1.87 1.81 1.71 1.41 1.77 1.652.13 2.03 2.11 2.08

Examples 1-8 all qualified as MB oils whereas comparative examples A toD failed to qualify as MB oils. Examples 1-8 has lower frictioncoefficients (<0.1), which means the compositions have improved frictionbenefits over comparative examples A to D. The MB oils all meet OEMrequirements for friction and fuel economy performance in four cyclegasoline engines of motorcycles equipped with a dry clutch.

It will be understood that various modifications may be made to theembodiments disclosed herein. Therefore, the above description shouldnot be construed as limiting, but merely as exemplifications ofpreferred embodiments. For example, the functions described above andimplemented as the best mode for operating the present invention are forillustration purposes only. Other arrangements and methods may beimplemented by those skilled in the art without departing from the scopeand spirit of this invention. Moreover, those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

1. A MoDTC-free lubricating oil composition for motorcycles whichcomprises an engine and a clutch, wherein the composition comprises: a.a major amount of an oil of lubricating viscosity, b. a molybdenumcompound, and c. a salicylate detergent having a TBN 100-450 on activebasis, in an amount of from 2.8 to 5.8 wt. %, wherein the ratio ofcomponent (c) to (b) is from 2.8 to 7.5, and wherein the salicylatedetergent is derived from C₁₄₋₁₈ normal alpha olefins.
 2. Thelubricating oil composition of claim 1, wherein the molybdenum compoundis a molybdenum succinimide.
 3. The lubricating oil composition of claim1, wherein the salicylate detergent has a TBN of 150-450.
 4. Thelubricating oil composition of claim 1, wherein the salicylate detergenthas a TBN of 200-400.
 5. The lubricating oil composition of claim 1,wherein the salicylate detergent has a TBN of 250-400.
 6. Thelubricating oil composition of claim 1, wherein the salicylate detergenthas a TBN of 250-350.
 7. (canceled)
 8. The lubricating oil compositionof claim 1, wherein the composition satisfies the system frictionperformance for JASO MB in the JASO T903.2011 test.
 9. (canceled)
 10. Amethod for lubricating the engine of a motorcycle which comprises anengine and a clutch, with a MoDTC-free lubricating oil composition,wherein the composition comprises: a. a major amount of an oil oflubricating viscosity, b. a molybdenum compound, and c. a salicylatedetergent having a TBN 100-450 on active basis, in an amount of from 2.8to 5.8 wt. %, wherein the ratio of component (c) to (b) is from 2.8 to7.5, wherein the composition lubricates the engine but not the clutch,and wherein the the salicylate detergent is derived from C₁₄₋₁₈ normalalpha olefins.
 11. The method of claim 10, wherein the molybdenumcompound is a molybdenum succinimide.
 12. The method of claim 10,wherein the salicylate detergent has a TBN 150-450.
 13. The method ofclaim 10, wherein the salicylate detergent has a TBN 200-400
 14. Themethod of claim 10, wherein the salicylate detergent has a TBN 250-400.15. The method of claim 10, wherein the salicylate detergent has a TBN250-350.
 16. (canceled)
 17. The method of claim 10, wherein the clutchis a dry clutch.
 18. A motorcycle having an engine, a clutch, and aMoDTC-free lubricating oil composition, wherein the compositioncomprises: a. a major amount of an oil of lubricating viscosity, b. amolybdenum compound, and c. a salicylate detergent having a TBN 100-450on active basis, in an amount of from 2.8 to 5.8 wt. %, wherein theratio of component (c) to (b) is from 2.8 to 7.5, and wherein thecomposition lubricates the engine but not the clutch.
 19. The motorcycleof claim 18, wherein the clutch is a dry clutch.